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Re: Re: Re: Bug in the multi interface? (curl_multi_wait returns 0)

From: Clemens Gruber <>
Date: Tue, 19 Feb 2013 14:31:10 +0100


I removed the check for !numfds and now it works perfectly for both
versions, with c-ares and the threaded resolver. Calling
curl_multi_perform if numfds is 0 seems not to be a problem.
Anyway, c-ares is a little bit faster in my case, so I'll stick with that.

Thank you very much for your assistance!


> This is due to a faulty assumption on your behalf, possibly induced by not
> having this explained properly in the man page.
> The difference you see between the two versions is probably there because you
> have built them with different resolver backends - or just that the code paths
> are a little bit different between the versions.
> The thing is that curl_multi_wait() can very well return zero 'numfds' without
> that being a problem - that's also why it returns OK for that situation. In
> some cases libcurl simply doesn't have any file descriptors to wait on and
> then it can't return any with activity.
> I can repeat this scenario with using the threaded resolver but it does not
> happen when I build with c-ares instead.
> -- /

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Received on 2013-02-19